Suture (anatomy)
Suture | |
---|---|
Details | |
Identifiers | |
Latin | sutura |
TA98 | A03.0.00.008 |
TA2 | 1522 |
FMA | 7493 |
Anatomical terminology |
In anatomy, a suture is a fairly rigid joint between two or more hard elements of an organism, with or without significant overlap of the elements.[1]
Sutures are found in the skeletons or exoskeletons of a wide range of animals, in both invertebrates and vertebrates. Sutures are found in animals with hard parts from the Cambrian period to the present day. Sutures were and are formed by several different methods, and they exist between hard parts that are made from several different materials.
Vertebrate skeletons
The skeletons of vertebrate animals (fish, amphibians, reptiles, birds, and mammals) are made of bone, in which the main rigid ingredient is calcium phosphate.
Cranial sutures
The
Sutures in the ankles of land vertebrates
In the type of
Invertebrate exoskeletons
In molluscs
The shells of most
Sutures in the shells of cephalopods
In
The septa are joined to the external shell by sutures formed by repeated invagination (they interlock like pieces of a jigsaw puzzle). The sutures are visible from the outside and often form complex and elaborate patterns.[5]
The suture in the shells of gastropods
Nearly all snail shells (except for the shells of
Each complete rotation of this spirally-arranged tube is called a whorl. The whorls of a snail shell usually overlap one another, forming a spire. Where the whorls overlap, there is usually a clear (if narrow) indentation. This indentation forms a visible line, which is continuous and reaches from the apex of the shell to the aperture; this line is the suture.
Details of the suture are often useful in discriminating one species from another, for example, sometimes the suture is channeled.
The suture also provides a sort of geographic marker from which one can refer to the positioning of patterning or sculpture, where that is relevant: for example some species have a darker or lighter subsutural band on the shell.[6]
When an angulation of the whorls occurs, the space between it and the suture above it (i.e. the abaxial edge of the sutural ramp) constitutes the area known as the "shoulder" of the shell. The shoulder angle may be simple or keeled, and may sometimes have nodes or spines
In arthropods
Sutures in the carapaces of trilobites
A trilobite's carapace consisted of calcite and calcium phosphate deposited on a lattice (framework) of chitin (a polysaccharide).[7]
The trilobite body is divided into three major sections: a
In many species, the cephalon had sutures running from back to front round the outside edges of the eyes. These sutures divided the cephalon into three pieces.
The sutures in trilobites' cephalons were unusual because it seems their main function was to create weaknesses, which made it easy for this part of the carapace ("armor") to split when the animal needed to molt.[7]
References
- ISBN 978-1-947172-04-3. Retrieved 16 April 2023.
- PMID 7887126.
- ^ Archosauromorpha: Archosauria - Palaeos Archived 2005-04-05 at the Wayback Machine
- ISBN 0-03-025982-7.)
{{cite book}}
: CS1 maint: multiple names: authors list (link - ^ Cephalopoda Glossary - Palaeos
- ^ "Palaeos Metazoa: Mollusca: Cyrtosoma: Cephalopoda: Glossary". Palaeos. Retrieved 13 Jun 2010.
- ^ ISBN 0375406255.